Method of and apparatus for the thermolytic decomposition of heavy liquid hydrocarbons



Dec. Q, 1952 MQRA 2,621,150

METHOD OF AND APPARATUS FOR THE THERMOLYTIC DECOMPOSITION OF HEAVYLIQUID HYDROCARBONS Filed Dec. 20, 1949 INVENTUR I lav-W W) ATTORNEYPatented Dec. 9, 1952 METHOD OF AND APPARATUS FOR THE THERMOLYTICDECOMPOSITION OF HEAVY LIQUID HYDROCARBONS Fernando M. Mora, BuenosAires, Argentina Application December 20, 1949, Serial No. 134,092 InParaguay November 8, 1949 9 Claims.

The present invention refers to a process for obtaining at low cost aseries of valuable products, especially carburetants for internalcombustion engines.

The process according to the present invention is based on the use of astarting material which, even though known per se, has never beenemployed heretofore as a source for obtaining carburetants, fuels forgeneral use, solvents and generally a series of highly desirableproducts.

In fact, the carbonization of wood which is car ried out in practicallyall countries of the world in order to obtain charcoal is effected undersuch operating conditions that all those products which are not charcoalsuch as the substances given off in the form of gases, are waste, andnothing is done in order to prevent them from freely escaping into theatmosphere. Among the products thus lost, there is vegetable tar whichcomprises within its heterogeneous composition, light, medium and heavyoils.

As the result of a series of experiments, it has now been discoveredthat it is possible to obtain by a highly economical process, a seriesof very valuable products if the aforementioned tar is subjected tomolecular disintegration preferably in one single step. The inventiontherefore essentially resides in the aforementioned feature and isdistinguished from prior art by the fact that it consists in obtainingthe products referred to by means of one single operation from onesingle starting material. This means to say that instead of obtainingcomplex products from a mixture of a number of components separately andindependently produced, they are obtained directly.

The process provides considerable advantages since it does away with thesystem of fractional or individual production of the various components,which system is unavoidably expensive. The invention renders possiblethe production, on a commercial scale and at considerably reduced cost,of products such as carburetants and solvents which as is well known,are highly desirable products.

More particularly, it may be said that the process according to theinstant invention consists in obtaining a mixture of aliphatic andaromatic hydrocarbons by means of molecular disintegration in one singlestep, from vegetable tars.

It will be appreciated that within the essential. aspect of theinvention which has just been explained, the process may be carried outin a great number of ways which will be evident to those familiar withthe art.

The molecular disintegration or breaking up of the vegetable tar may bebrought about by any known method such as pyrogenation, hydrogenation orcracking. Satisfactory results have been obtained by effecting thepyrogenation or heat treatment under specific working conditions inorder to bring about successive chemical shocks upon the heavy moleculesof the tar which tend to dissociate within the range of convenientdistillation temperatures until the almost complete transformationthereof into lighter molecules is obtained, and this is achieved bysystematical rectification at the very moment of pyrogenation. Anequipment permitting the desired results to be obtained has beenillustrated by way of example in the accompanying drawings in which theseveral parts of the equipment have been represented somewhatschematically.

The present invention is directedto a method of molecularlydisintegrating or cracking heavy tar or heavy hydrocarbon comprisingspraying a film of the heavy tar or hydrocarbon against a surface heatedto a cracking temperature, retaining the tar on the heated surface whileit is being cracked, progressively moving the locus of spray tocontinuously spray new increments of tar onto successive surface areasheated to the disintegrating or cracking temperature of the hydrocarbonbeing treated, removing from said heated surface solid residues producedduring cracking, and recovering the disintegrated or cracked fractionswhich are mainly composed of hydrocarbons of the benzene series, such asbenzene, toluene, xylene, cumene, retene, and the like. In the preferredform of the invention, the heated surface is a cracking tube.

From an apparatus standpoint, the invention broadly comprises anapparatus for cracking a hydrocarbon entity comprising the combinationof a cracking surface adapted to be heated to the cracking temperature,means for progressively moving a spray head along said cracking surface,means for removing from the latter the decomposition residue producedduring cracking of the hydrocarbon including tar, and means forrecovering the disintegrated or cracked fractions. In the preferred formof the invention, the spray head reciprocates along said crackingsurface and during its reciprocation emits successive increments of ahydrocarbon spray against successive areas of the cracking surface. Thecracking surface is preferably in the form of a cracking tube. In oneform of the invention the spray head is secured to a piston, said pistonduring its reciprocatory movement removing from the interior 3 wall ofthe cracking surface decomposition residue produced during the crackingof a heavy hydrocarbon.

In the drawings equal or corresponding parts have been designated by thesame numerals or characters.

Referring to the drawing, it will be seen that a is a metal cylinder ofrelatively small diameter as compared with its length, mounted in heatexchange relationship with a hearth I of a furnace b provided with agrill 2 for solid fuel. Within the cylinder at there is arranged apiston 3 mounted on a piston-rod which is longitudinally reciprocated bysuitable means (not shown). The working face of the piston, which. is ofsimple effect, is provided with an atomizing head 5 adapted to injectinto the cylinder a finely subdivided spray of liquid tar fed throughthe bore of hollow piston-rod 4. Piston-rod' l is fed from an auxiliaryequipment comprising a pump. 0 connected to the tar reservoir (notshown) through a'pipe 9. Through another pipe 1 the tar'is led into anintermediate reservoir (1 which in turn communicates through pipe 8 withthe piston pump device e, this latter being provided for the purpose offeeding th liquid through flexible hose '9 into the'bore of rod 4. Allthe movements which must take place in order to operate the movableparts'of theequipment are effected by means of a'transmission system fdriven by "engine 9.

It'will be noticed that cylinder (1 is provided with two sumpslfl intowhich the carbon residues entrained by'piston 3 are discharged. As-

sociated with cylinder at isfarranged a rectifying column it throughwhich the gases forthcoming from the disintegration of the tar withinthe cylinder are passed. The rectifying column is provided'with a numberof rectifying plates H and an upper outlet lz'fordischarging thepartially rectified gases. I

In accordance withthe foregoing, the tar from theauxiliary pumpingequipment enters cylinder a and isprojected in the form of a fine sprayagainstthe inner walls-of-said cylinder which areheated to approximately500 C., by furnace b. When the tar particles strike against the thusheated inner walls of cylinder a, the molecules are cracked or broken upbecause of the lower stability of the heavier molecules. The lightfractions, which are those desired to be obtained, then enter therectifying column h and are finally led towards storage tanks or anyother suitable storage means. Those molecules which have not beenmodified within cylinder a may be recycled thereto for furthertreatment.

The light fractionsare mainly composed of hydrocarbons of the benzeneseries such as benzene, toluene, xylene, cumene, retene, crysene andsaturated acyclic fatty hydrocarbons. in experimental tests it has beenpossible to obtain, by means of the equipment described, up to 28% ofaromatic and aliphatic hydrocarbons havin boilingpoints comprisedbetween 70 C and 200 0., said percentage being based on the amount oftar treated. 'The compositions obtained from the process according tothe invention may show some variations in their chemical structureaccording to the wood from which the tar treated has been produced, andaccording to the particular'operating conditions of a given treatment,etc. In view of the variety of factors which influence the'chemicalcomposition of the distillate obtained, it'will be evident that thecharacteristic properties of the liquids obtained will vary accordingly,in the same way for instance as oils obtained from different crudes willvary according to the crudes. In connection with the present inventionthese differences do not adversely affect the suitability of the finalproducts for the practical purposes already mentioned.

The compositions obtained show, among other desirable characteristics,the property of forming stable mixtures with normal grade ethyl alcohol(94/97 GL) and thus they are most suitable for use in carburetantmixtures in conjunction with ethyl alcohol, in internal combustionengines. The compositions obtained in accordance with the presentinvention may also be employed as fuels for other purposes, solvents forpaints, varnishes, etc.

It will be understood that the process of the present invention may bevaried or modified without departing from the essence of the inventionwhich is defined in the annexed claims.

I claim:

1. In the method of cracking tar, the steps comprising spraying a filmof tar against a surface heated to a cracking temperature, retaining thetar film on the heated surface, progressively moving the locus of sprayto continuously spray new increments of tar on successive surface areasheated to the cracking temperature, progressively removing from saidheated surface solid residues produced during cracking, and recoveringthe cracked vapors.

2. In the method of cracking tar, the steps comprising spraying a filmof tar against the surface of a cracking tube heated to a crackingtemperature, retaining the tar film on the heated surface of the tube,progressively moving the locus of spray to continuously spray newincrements of tar on successive surface areas of the heated crackingtube, progressively removing from said tube solid residues producedduring cracking, and recovering the cracked vapors.

3. In an apparatus for cracking tar, a horizontally disposed elongatedcylinder, a furnace arranged in surrounding relation with respect tosaid cylinder, a piston of slightly less diameter than the diameter ofsaid cylinder reciprocably arranged in said cylinder, an atomizin headarranged on the working face of the piston and adapted to inject intothe cylinder a finely subdivided spray of fluid, a hollow horizonallydisposed piston rod connected to said piston, a feedingassembly forsupplyin tar to said piston rod, a pair of vertically disposed spacedparallel sumps arranged at opposite ends of said cylinder for receivingcarbon residue, a vertically disposed rectifying column arranged incommunication with said cylinder and provided with a plurality ofrectifying plates, and an outlet arranged on the upper end of saidrectifying column for the egression therethrough of partially rectifiedgases.

4. In an apparatus for cracking a heavy hydrocarbon, the combination ofa cracking surface adapted to be heated to a cracking temperature, meansfor reciprocating a spray head along said cracking surface while thespray head during one-stroke of itstravelemits successive increments ofa hydrocarbon spray against successive surface areas of said crackingsurface, means for removing from the latter during the return stroke ofthe spray head decomposition residue producedduring the cracking of theheavy hydrocarbonyand means for recovering the cracked vapors.

5. In an apparatus for cracking a heavy hydrocarbon, the combination ofa substantially horizontal cracking tube, means for progressively movinga spray head in one direction along said cracking tube while the sprayhead emits a hydrocarbon spray against the cracking tube, means forremoving from the latter during the movement of the spray head in anopposite direction the decomposition products produced during crackingof the hydrocarbon, and means for recoverin the cracked vapors.

6. In an apparatus for cracking a heavy hydrocarbon, the combination ofa substantially horizontal cracking tube, a piston reciprocating in saidtube, a spray head secured to the piston for emitting a hydrocarbonspray against the interior wall of said tube, means for feeding ahydrocarbon to said spray head, said piston durin its return strokeremoving from the interior wall of the tube solid decomposition productsproduced during the cracking of the hydrocarbon, and means forrecovering the cracked vapors.

7. In an apparatus for cracking a heavy hydrocarbon, the combination ofa substantially horizontal cracking tube, a piston reciprocating in saidtube, a spray head secured to the piston for emitting a hydrocarbonspray against the interior wall of said tube, a hollow piston rodoperatively connected to said piston and said spray head for feedinghydrocarbon to said spray head, said piston during its return strokeremovin from the interior wall of the tube the solid decompositionproducts produced during the cracking of the hydrocarbon, and means forrecovering the cracked vapors.

8. In an apparatus for cracking a heavy hydrocarbon, the combination ofa substantially horizontal cracking tube, a piston reciprocating in saidtube, a spray head secured to the piston for emitting a hydrocarbonspray against the interior wall of said tube, means for feeding ahydrocarbon to said spray head, said piston during its return strokeremoving from the interior wall of the tube solid decomposition productsproduced during the cracking of the hydrocarbon, means ior recoveringthe cracked vapors, and spacedly disposed means operatively connected tosaid tube for receiving solid decomposition products removed by saidpiston from the interior wall of the tube.

9. In an apparatus for cracking a heavy hydrocarbon, the combination ofa substantially horizontal cracking tube, a piston reciprocating in saidtube, a spray head secured to the piston for emitting a hydrocarbonspray against the interior wall of said tube, means for feeding ahydrocarbon to said spray head, said piston during its return strokeremoving from the interior wall of the tube solid decomposition productsproduced during the cracking of the hydrocarbon, means for recoveringthe cracked vapors, spacedly disposed means operatively connected tosaid tube for receiving solid decomposition products removed by saidpiston from the interior wall of the tube, and means for removing saiddecomposition products from the cracking tube on the pistonreciprocating in said tube.

FERNANDO M. MORA.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,304,212 Slocum et al. May 20,1919 1,680,541 Hancock et al. Aug. 14, 1928 1,911,909 Maruhn et a1 May30, 1933 FOREIGN PATENTS Number Country Date 50,301 Sweden Aug. 6, 1919OTHER REFERENCES EgloiT: The Cracking Process, a Universal Source ofMotor Fuel, published by Universal Oil Products Company (1928) 87 pages.

Morrell et al.: Motor Fuels and Other Products from the Crackin of WoodTars. I. and E. Chem. vol. 2 1929) pgs. 537-542,

1. IN THE METHOD OF CARACKING TAR, THE STEPS COMPRISING SPREAYING A FILMOF TAR AGAINST A SURFACE HEATED TO A CRACKING TEMPERATURE, RETAINING THETAR FILM ON THE HEATED SURFACE, PROGRESSIVELY MOVING THE LOCUS OF SPRAYTO CONTINUOUSLY SPRAY NEW INCREMENTS OF TAR ON SUCCESSIVE SURFACE AREASHEATED TO THE CRACKING TEMPERATURE PROGRESSIVELY REMOVING FROM SAIDHEATED SURFACE SOLID RESIDUES PRODUCED DURING CRACKING, AND RECOVERINGTHE CRACKED VAPORS.